The sampling of a portion of a tissue is often necessary in many humans and animals, particularly in the diagnosis and treatment of patients with cancerous tumours, pre-malignant conditions and other diseases and disorders. In particular, it is used to exclude malignancy. A biopsy may be performed when a lesion, or an abnormal area within a tissue that could possibly represent cancerous changes, is detected. The biopsy is performed to determine the nature of the lesion or abnormal area.
Traditionally, biopsies have been performed using conventional, or ‘open’ surgery, which involves making a large incision on the skin and dissection down to the area in question and removing the lesion. Haemostasis is then achieved using diathermy, or an electrosurgical system, in direct contact with the bleeding tissue to stop further haemorrhage. With the advent of minimally invasive biopsy techniques, it is now possible to achieve tissue biopsy through small incisions in the skin, measuring 3 to 5 mm in length. A biopsy instrument is usually constructed as a needle-like instrument with a diameter of less than 5 mm or that which is equivalent to the intended size of the skin incision and is passed from the skin to the area in question under some form of image guidance. This is known as a percutaneous approach and is commonly performed using either ultrasound techniques or x-rays for guidance. A tract therefore needs to be created from the entry point on the skin to the lesion.
Sharp dissection of vascular tissue is usually involved in demarcating the tract and removing tissue. This often results in bleeding which may occasionally be uncontrolled. A technique of achieving haemostasis is therefore essential. It is evident that because of its approach, bleeding poses a challenge for image-guided minimally invasive biopsy techniques as haemostasis cannot be achieved in the traditional manner as would be possible in conventional biopsies.
There is a paucity of devices created to prevent uncontrolled bleeding in a consistent and effective manner following percutaneous minimally invasive biopsies. Depending on the type of tissue sampled, methods that have been employed include the application of physical pressure, adrenaline injection, argon laser coagulation, or the recent use biodegradable hydrogel polymers (http://www.surgery.arizona.edu/research/grants-research/biodegradable-hydrogels.htm) or fibrin glue which act as tissue sealants and form a physical bond with the cut surface of the tissue. Although some of these techniques have been proven useful in conventional surgery, the requirements for negotiating the tract from the skin to the lesion before its application precludes its accurate and effective use in the setting of minimally invasive percutaneous biopsy techniques. Based on current methods, effective haemostasis may not be achieved and continued bleeding or a large haematoma might result. This may require further treatment with conventional surgery. In such cases, the patient is subject to additional discomfort and distress and the advantage of a minimally invasive procedure is negated.
There is therefore a need in the art for a device that can achieve haemostasis soon after a biopsy and/or tissue sampling, so as to cause minimal bleeding and discomfort to the patient.